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Expanding graft numbers combining strip and FUE in the same session: effect on linear wound closure forcesAkaki Tsilosani, MD, PhD Tbilisi, Georgia clinic@talizi.ge

IntroductionTo achieve 5,000 follicular units (FUs) in a case of high

donor density (80-90 FUs per cm²), it is necessary to harvest a strip of not less than 60cm². When strip length is limited to 25-30cm, the width of the strip in the center has to be increased up to 3cm. This is only possible when there is very good scalp flexibility. Donor zone closure under such tension increases the risk of wide donor scar formation. Though scalp exercises before surgery can improve laxity and increase yield by anywhere from 500-1,500 FUs,1 often this is not sufficient.

In order to reduce strip width without decreasing the number of grafts transplanted during an operation, in 2006 we decided to combine FU strip excision (FUS) with FU ex-traction (FUE). Conducting the operation using the combined techniques of FUE and strip excision is very simple. First, the strip edges subject to excision are marked. Strip width in such cases seldom exceeds 2cm (the length usually ranges from 20-28cm). Above and below the strip edges, 500-1,500 grafts are harvested using the FUE method followed by a strip excision; this generates from 2,500 up to 3,500 additional grafts depending on the density. As a result, 3,000-5,000 follicular units are obtained for transplantation (Figure 1).

expanding the area by 10-15%). Strip average width varied from 1.2-2.0cm (after the excision, the average strip width shrank to 1.0-1.6cm). The maximum width of a strip to be excised was determined based on the clinical estimation of scalp mobility of a particular patient, though all widths were extremely large for these patients.

In all subjects, scalp tension during donor wound closure was measured. To achieve this, retention sutures involving the dermis at equidistant points 5-8cm from the wound center were placed. Retention sutures placed on the upper wall of the wound were attached to one dynamometer, and sutures put on the lower wall of the wound were attached to another (Figure 2). Next, the assistant accurately moved the dynamometers in one plane at right angles to the wound in different directions, stretching the wound edges until the moment of contact. Readings of both dynamometers were registered. The sutures were then removed.

This method not only provides the ability to harvest the necessary quantity of grafts, but also substantially decreases tension on the donor wound closure.

The purpose of this study was to compare and analyze scalp tension forces while closing donor wounds immedi-ately following strip excision and before and after additional FUE extraction in patients with low donor density and poor laxity.

Materials and MethodsTwenty patients aged 25-55 with poor scalp laxity and

with low or average donor density underwent hair transplan-tation with the purpose of correcting male pattern alopecia of high degree (Norwood IV-VII). The quantity of grafts obtained via a strip varied from 2,500 up to 3,500 follicular units. Using a single-blade scalpel, an 18-28cm–long ellipse shape was excised from the donor area under local anesthe-sia. The maximum width in the occipital prominence was 1.8-2.8cm (the measurement was taken following anesthesia

Figure 1. Donor area after 1,500 FUs extracted and strip excision giving 3,520 FUs—total of 5,020 grafts.

Figure 2. Scalp tension forces measurement after strip excision.

Scalp tension forces during donor wound closure were determined as the sum of forces applied to the upper and lower ends of the wound necessary for adjoining its edges. The obtained data was statistically processed.

The wound was then temporarily packed and we pro-ceeded with the FUE extraction of grafts above and below the strip donor area to try to obtain at least 30% additional grafts than was generated through strip excision. We used 0.75 and 1.0mm punches for graft extraction. The quantity of grafts obtained with FUE varied from 450-1,500 FUs (Figure 3). At the completion of the FUE procedure, scalp tension was measured a second time as described above (Figure 4). Next, a lower edge trichophytic closure of the wound with one-layer continuous 5-0 monocryl was performed.

ResultsThe power required to approximate the donor wound

edges (scalp tension power) without the additional FUE procedure varied from 3.4-8.8 kg-f depending on scalp flexibility and the number of obtained grafts (strip width). The average tension power in cases of transplantation of 2,505-3,544 FUs was 4.92±0.09kg-f. After FUE extraction of 450-1,500 FUs, the necessary power for approximation was 2.1-5.3kg-f, average 2.95kg-f, p<0.001% (Table 1).

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It was observed that if, through FUE, at least 30% ad-ditional grafts are generated, then compression forces decreased by half during wound closure. For example, if a patient had 1,200 FUs extracted above and below the excised strip (which generated 3,306 grafts), this would decrease scalp tension power from 6.4kg-f to 3.1kg-f. If FUE would generate less than 30% of the quantity of strip grafts (e.g., 450 FUs per 2,512-graft strip), then the compression force during wound closure did not decrease significantly. On average, after FUE, scalp tension power varied from 4.92-2.95kg-f, which accounts for a 40% decrease. Donor wounds in all patients healed as cosmetically acceptable scars (Figure 5).

DiscussionIf there is a possibility of trans-

planting the needed amount of grafts in one session, the patient only ben-efits for the following reasons:1. The optimal cosmetic benefit of

the hair transplant surgery is ob-tained earlier (1 year after the first session, instead of 1 year after the subsequent, or last, session).

2. All the inconveniences related to the surgery are experienced only one time.

3. As long as one large session is offered at a discounted cost per graft, the patient benefits eco-nomically.

Expanding graft numbers from page 121

Large sessions have additional advantages. In our opin-ion, there is a better final donor scar (even with the donor strip being wider, the final result will be better than after 2 or 3 incisions in the same place). There is no previous scar deforming the anatomy, so there is less risk of damage to the nerves and arteries. In many cases, the first session grows best,2 maybe because of the hypothesis of less recipient area scarring leading to better growth or because of some other reason, based on the fact that growth is much better on the virgin scalp.

Many surgeons, however, believe that performing large sessions is associated with lots of difficulties. After analyz-ing these problems, we can list three possible complicating factors:1. Placement of large numbers of grafts close to each other

may compromise the vascularity of the recipient area, which can lead to decreased graft survival.

2. Long operative time (8-12 hours) increases the risk of time out of body and graft dehydration, and tires the patient and staff, which can affect the quality of the work.

Figure 3. Donor area immediately after strip excision and 1,200 FUs extracted.

Figure 4. Scalp tension forces measurement after strip excision and 1,200 FUs extracted.

Tension forces applied to the upper and lower edges of the wound necessary for their adjoining kg-f N

Number of transplanted grafts

Maximum width of donor strip (cm)

Number of additional FU grafts

1 3,306 2.60 1,200 3.2+3.2=6.4 1.6+1.5=3.12 2,568 2.20 800 2.0+2.0=4.0 1.4+1.5=2.93 2,540 2.00 1,000 2.5+2.5=5.0 1.5+1.0=2.54 2,500 1.90 600 2.5+2.5=5.0 1.5+1.6=3.15 3,544 2.40 1,200 3.0+3.2=6.2 1.8+2.0=3.86 2,525 2.00 600 2.2+2.3=4.5 1.5+1.5=3.07 2,580 2.30 800 1.9+2.0=3.9 1.1+1.0=2.18 3,032 2.40 1,000 2.7+2.7=5.4 1.5+1.8=3.39 2,600 2.00 800 2.3+2.2=4.5 1.2+1.2=2.410 2,860 2.30 1,000 2.6+2.5=5.1 1.2+1.2=2.411 2,910 2.50 1,000 1.9+2.0=3.9 1.2+1.2=2.412 2,772 2.20 1,000 2.8+3.0=5.8 1.2+1.4=2.613 2,545 2.20 700 2.2+2.4=4.6 1.5+1.5=3.014 2,622 2.60 700 4.6+4.2=8.8 2.6+2.7=5.315 3,520 2.50 1,500 2.8+2.9=5.7 1.5+1.5=3.016 3,152 2.40 450 2.4+2.1=4.5 1.4+1.5=2.917 2,622 2.00 600 1.8+1.6=3.4 1.4+1.6=3.018 2,512 1.80 450 1.7+1.7=3.4 1.2+1.6=2.819 2,705 2.20 800 2.3+2.4=4.7 1.2+1.2=2.420 2,510 2.40 500 1.8+1.7=3.5 1.4+1.5=2.9M 2,943 2.36 4.92 2.95m 0.09 0.02t=22.23 p<0.001

After strip excision After strip excisionand FUE

Table 1.

Figure 5. One of the observed patient’s donor area after 8 months.

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3. Wide strip excision in patients with low donor density and poor scalp flexibility causes an unacceptable scar.

On the other hand, large sessions are performed on Norwood classes IV-VII, in whom the recipient area exceeds 100cm². Transplanting even 4,000-6,000 FUs results in an average density of less than 50 FU/cm². Recent research has shown that small (less than 1mm), sharp instruments used for recipient site creation do not compromise blood supply and do not decrease graft survival, even with densities of 70 FU/cm.2-4 Today, 40-50 FUs per cm² is considered safe.

We think that large sessions are impossible without a very large staff. While performing them, we always pre-make recipient sites and work in three teams: I – surgeon and 1-2 nurses II – cutters (1 leading cutter for slivering and 8 other

cutters) III – implanters (3 experienced implanters and 1-2 as-

sistants for cleaning and drying recipient sites)

In our office, transplanting 5,000 grafts, on average, takes less than 6 hours, so we think that the only problem with performing large sessions is poor donor supply in the patient with low donor density and poor flexibility. The combination of strip surgery and FUE increases the duration and the cost of the operation; nevertheless, we believe this is the optimal option to perform large sessions in patients with poor donor laxity and density.

References1. Wong, J. Preoperative care for super mega-sessions. In:

D. Pathomvanich and K. Imagawa, eds. Hair Restoration Surgery in Asians. Springer. 2010; 81-82.

2. Seager, D.J. The “one-pass hair transplant”—a six-year perspective. Hair Transplant Forum Int’l. 2002; 12(5):1-6.

3. Nakatsui, T., J. Wong, and D. Groot. Survival of densely packed follicular unit grafts using the lateral slit tech-nique. Dermatol Surg. 2008; 34(8):1016-1025.

A note from Dr. Robert H. True New York, New York

FUE and strip donor excision (FUT) are increasingly being seen as complementary techniques. At the 2009 ISHRS Annual Meeting in Amsterdam, I presented several models in which FUE and FUT are both performed in the same procedure. One of the models is to do as described in this paper; that is, to perform FUE immediately adja-cent to the sutured FUT incision. While this approach can significantly add to the graft harvest, I have come to prefer the approach where the FUE zone is separate and placed 1-2cm above the FUT zone. In my hands, this yields the greatest additional harvest. In all cases, I remove the strip first and suture the incision before commencing FUE. I think this is the most efficient approach because I am making grafts at the same time as others are being dissected from the strip.

As to the effect of FUE on diminishing strip wound closure tension, I would be hesitant to infer causality. Dr. Mike Beehner and others have observed that waiting 45-60 minutes before closure reduces wound tension due to reabsorption of tumescent solution. Dr. Tsilosani notes that with smaller FUE harvests the reduction of wound tension was less. Presumably, these smaller harvests took less time and the wounds were closed sooner, whereas the time interval with larger harvests being longer may have allowed for the reabsorption effect to fully develop. One way to evaluate this would be to delay closure 45-60 minutes and perform FUE above and below the incision to only half of the wound. If there was no difference in reduction of closure tension between the two sides, any effect due to FUE could be excluded.

4. Tsilosani, A. One hundred follicular units transplanted into 1cm² can achieve a survival rate greater than 90%. Hair Transplant Forum Int’l. 2009; (19)1:1.✧